DR. J. MURIE ON THE FORM AND STRUCTURE OF THE MANATEE. 157 
Manatee. This has a fleshy origin from the entire length of the prominent ridge of 
the outer occipital, thence is directed nearly vertically outwards and backwards, 
marked by limiting the anterior flattened surface of the shoulder. It continues 
obliquely round the head of the humerus immediately in front of the deltoid, at 
this part resembling the latter in shape, and is inserted on the inner and anterior 
side of the neck of the humerus by a very short, but strong, tendon. The humeral 
attachment is on a level with that of the deltoid, above that of the pectoralis major, 
and close to the front upper edge of the biceps. 
Although a clavicle is absent, a muscle corresponding to a levator clavicule (?) exists. 
It is a narrow fleshy slip arising from the paramastoid directly behind the stylo-hyal 
and origin of the digastric. Coursing downwards and backwards parallel with the 
anterior border of the cephalo-humeral, it becomes fused with this last at the head of 
the humerus. ‘There is a slight transverse fibrous line of demarcation where the levator 
terminates; and this, it may be, is a representative of an osseous clavicle. At the head 
the muscle is in close relation with the hinder part of the parotid gland; and a small 
portion of the glandular substance and several vessels separate it from the cephalo- 
humeral. 
The two above muscles apparently have a combined action, and drag the pectoral 
extremity forwards, upwards, and fully rotate it outwards. They doubtless oppose the 
latissimus dorsi and teres major; but the shortness of their leverage must detract from 
any great power. 
The pectoralis minor agrees with the pectoralis major in being relatively long and 
narrow. It springs from the anterior portion of the rectus abdominis over the fibrous 
cords or sternal cartilages of the second and third ribs, and from the projecting sharp 
angle of the sternum, not reaching, however, the median line. As the muscle trends 
forwards it narrows slightly, and finally is inserted into the head of the humerus. 
Several large glands lie beneath the muscle; and axillary vessels and nerves pass 
beneath it, the rete mirabile being closest to its deep surface. 
The pectoralis major muscle is thick and powerful, though relatively narrow. It has 
origin from the whole length of the sternum, and from the median line of the abdomen 
two inches beyond the ensiform cartilage, where it overlaps a small inner portion of 
the anterior inner edge of the rectus. The muscular fibres take a direction obliquely 
or sharply forwards and outwards, and are inserted, by a very strong short tendon, 
into the upper portion of the lower third of the thoracic aspect of the shaft of the 
humerus. There is only an indistinct division into sternal and manubrial portions, 
which might be overlooked, except that the former rolls somewhat round, or rather 
dips beneath, the anterior more fleshy moiety at the axilla. 
The humeral tendon of the pectoralis major while firmly implanted into the deep pit 
or continuation of the bicipital groove on the inner and lower aspect of the shaft of the 
bone, also possesses continuity with the radial segment of the forearm. Adduction of 
